Conveyor for mechanical street sweeper

ABSTRACT

There is described a squeegee style conveyor for a street sweeper in which the shaft connecting the lower pulleys has been removed to provide more space between the lower pulleys for larger objects to pass. The lower pulleys are supported on the conveyor tray by spindle hub assemblies.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to conveyors, particularlyconveyors for mechanical street sweepers, and to street sweeperscomprising conveyors.

[0003] 2. Description of the Prior Art

[0004] Different kinds of conveyors have been used in mechanical streetsweeping machines. There is the squeegee style conveyor that dragsmaterial along a conveyor tray and up to a hopper. There is thefull-width belt style that carries material up to a hopper on the top ofthe belt. There is also an auger system that dumps material onto anarrow belt conveyor that ends at a hopper. These systems all use twoshafts, one drive shaft and a corresponding driven shaft, located atopposite ends of the conveyor. The size of the material conveyed by suchconveyors is generally limited to the distance between the shaft and thelower surface of the conveyor.

[0005] In a “squeegee” or drag type conveyor, a number of spaced apartand usually somewhat flexible cleats or flights, commonly known as“squeegees”, is provided. Each squeegee is disposed across the width ofthe conveyor and is used to drag debris along a surface of a conveyortray, which is usually disposed immediately below and parallel to thelower straight span of the conveyor, in order to push the debris off thetop end of the conveyor tray into a hopper. It is preferable that thesqueegees be somewhat flexible in order to make substantially sealingsliding contact with the surface of the conveyor tray, so that debris,including mud and water, is dragged up the conveyor tray. The conveyortray may terminate at its lower end in a curved lower lip that followsthe arc of the distal edge of the squeegees as they arcuately traversethe bottom end of the conveyor. Two shafts, each connecting a pair ofpulleys or sprockets located at opposite ends of the conveyor, aregenerally used to drive the conveyor belt. Normally, the shaft at thetop end near the hopper drives the conveyor while the shaft near thebottom end idles and is driven in response to movement of the conveyorbelt.

[0006] A mechanical street sweeper is generally equipped with a hopperin which debris is stored after being swept up from a roadway. Thedebris is conveyed from the roadway to the hopper by means of theconveyor, which receives the debris from rotating brushes or brooms incontact with the road surface. As contractors increasingly use suchsweepers to pick up larger and larger objects, the conveyor must be ableto convey these larger objects to the hopper without plugging orstalling.

SUMMARY OF THE INVENTION

[0007] The present invention relates to a conveyor for a mechanicalstreet sweeper, in particular to a squeegee style conveyor, and tostreet sweepers comprising a conveyor.

[0008] Thus, there is provided a conveyor for a mechanical streetsweeper, the conveyor comprising: a conveyor tray having a firstlongitudinal end, a second longitudinal end and a surface adapted tohave debris conveyed thereon; a first set of laterally spaced apartrotational elements rotationally supported on the conveyor tray at thefirst end; a second set of laterally spaced apart rotational elementsrotationally supported on the conveyor tray at the second end defining alaterally unobstructed passageway through which debris may pass betweenthe second set of spaced apart rotational elements; a set of laterallyspaced apart parallel loops supported on and engaged with the set ofrotational elements and having laterally extending flights attached tothe loops at intervals along the loops, the loops and the sets ofrotational elements being located on the conveyor tray such that theflights travel along the conveyor tray to convey debris along thesurface; and, a drive means connected to either the first or the secondset of rotational elements for rotating the loops.

[0009] There is further provided a mechanical street sweeper comprising:a frame; a hopper supported by the frame for holding debris; a brushsupported by the frame for selective rotation in contact with a roadway;an inclined conveyor tray supported by the frame and having a firstlongitudinal end proximate the hopper adapted for delivering debris tothe hopper, a second longitudinal end proximate the brush adapted forreceiving debris from the brush and a surface adapted to have debrisconveyed thereon; a first set of laterally spaced apart rotationalelements rotationally supported on the frame or the conveyor trayproximate the first end of the conveyor tray; a second set of laterallyspaced apart rotational elements rotationally supported on the frame orthe conveyor tray proximate the second end of the conveyor tray anddefining a laterally unobstructed passageway between the second set ofrotational elements through which debris may pass from the brush to thesurface of the conveyor tray; a set of laterally spaced apart parallelloops supported on and engaged with the sets of rotational elements andhaving laterally extending flights attached to the loops at intervalsalong the loops, the loops and the sets of rotational elements beinglocated on the frame or the conveyor tray such that the flights travelalong the conveyor tray to convey debris along the surface; and, a drivemeans connected to either the first or the second set of rotationalelements for rotating the loops.

[0010] The present invention advantageously permits handling debris of avariety of sizes which may be found on roadways. For example, smalldebris such as sand, leaves and gravel normally found on residentialstreets and large debris such as blown tires, hubcaps and millings(chunks of pavement) often found on highways can all be picked up whilereducing the instances of jamming, plugging and/or stalling. Increasedclearance which permits such advantageous handling is facilitated in thepresent invention by the removal of the shaft at the end of the conveyorclosest to the roadway. The size of the debris that the street sweeperis able to pick up is accordingly no longer limited to the distancebetween the shaft and the surface of the conveyor tray.

[0011] Street sweepers generally include a frame, suspension, wheels, aninternal combustion engine and other standard vehicle components thatwill not be discussed here in any detail. The frame typically supports ahopper in which debris is housed until the debris can be disposed of ata site. The upper part of the hopper is open to receive debris from theconveyor. The frame also supports a brush or brushes for sweeping debrisoff the roadway. Typically there is at least one brush for selectiverotation in contact with a roadway whose rotation sweeps debris off theroadway onto the conveyor tray where it is conveyed by the conveyor upto the hopper. Drag shoes located laterally from the brush are alsogenerally employed to minimize the amount of debris which is thrownlaterally from the street sweeper.

[0012] The conveyor comprises a conveyor tray having a firstlongitudinal end that is proximate the hopper adapted for deliveringdebris to the hopper. The conveyor tray also has a second longitudinalend proximate the brush adapted for receiving debris from the brush. Theconveyor tray further has a surface adapted for having debris carriedthereon from the second end to the first end for delivery into thehopper. The conveyor tray is supported on the frame of the streetsweeper and is generally inclined from the roadway up to the hopper.

[0013] The conveyor further comprises two sets of laterally spaced apartrotational elements which are rotationally supported on either theconveyor tray or the frame of the street sweeper. Preferably therotational elements are supported on the conveyor tray to provide aunitized conveyor system that can be more easily put on or taken off theframe of the street sweeper. One set of laterally spaced apartrotational elements (i.e. the first set) is located at or proximate thefirst longitudinal end of the conveyor tray. The other set of laterallyspaced apart rotational elements (i.e. the second set) is located at orproximate the second longitudinal end of the conveyor tray. The firstset of rotational elements may be connected by a shaft that extendslaterally across and through the conveyor or may be unconnected in thisway. It is preferred to connect the first set by a solid shaft tofacilitate driving the conveyor.

[0014] The second set of rotational elements is supported on theconveyor tray or the frame in such a way as to at least partially openthe lateral space through the conveyor between the rotational elementsof the second set. This provides more room for debris to pass from thebrush to the surface of the conveyor tray permitting larger objects tobe conveyed up to the hopper. The second set of rotational elements maybe supported in any manner known in the art which opens the lateralspace between them, but it is preferred to use a manner which maximizesthe amount of room between the rotational elements. Advantageously, thesecond set of rotational elements may be independently supported on theconveyor tray or the frame, for example, by using spindle hub assembliessuch as those typically used on automobile and trailer wheels. Thespindle hub assemblies comprise bearings, optionally packed in grease,and preferably include a seal and dust cap to protect the bearings fromdebris in order to minimize the need for maintenance of the bearings.Two bearings may be advantageously employed. The first set of rotationalelements may also be supported in such a manner, if desired. Scraperssupported on the conveyor tray or the frame and located between the topand bottom of the loops just behind each rotational element of thesecond set may be used to help minimize buildup of dirt and other debrisat the second set of rotational elements.

[0015] Supported on and engaged with the rotational elements arelaterally spaced apart parallel loops. Each loop wraps around therotational elements of the first and second set which are located in thesame longitudinal line along the conveyor tray. In this way, a set ofendless, laterally spaced apart, parallel loops form the basis of theconveyor. Rotation of the loops is achieved through rotation of thefirst and/or second set of rotational elements by a drive means. It ispreferred to rotate the first set of rotational elements since this setis located farther from the roadway and does not come into regularcontact with debris.

[0016] While it is possible to have any number of rotational elementswithin a set, the width of the conveyor tray may place a practical limiton the number of rotational elements in each set. It is generallypreferred to use a pair of rotational elements in each set. Thus, theconveyor preferably comprises a first pair of rotational elements, asecond pair of rotational elements and a pair of belts.

[0017] It is also possible to have one or more other sets of laterallyspaced apart rotational elements rotationally supported on the conveyortray or the frame and located longitudinally between the first set andthe second set. These other sets of rotational elements are generallysmaller in diameter than, and located vertically higher in relation tothe surface of the conveyor tray than, the first and second sets ofrotational elements These other sets of rotational elements typicallyidle and may be used to help support the loops in the longitudinal spacebetween the first and second sets of rotational elements. These othersets of rotational elements may be connected by a solid shaft thatextends laterally across and through the conveyor or they may beunconnected in this way. The smaller diameter and the higher verticallocation of these other rotational elements helps in maximizing theincreased clearance realized by the conveyor of the present invention.

[0018] A wide variety of rotational elements useful in the presentinvention are known in the art. Advantageously, pulleys and/or sprocketsare used. When pulleys are used, the loop is a belt. When sprockets areused, the loop is a chain. It is possible to use a combination ofpulleys and sprockets, however, it is preferred to use either pulleys orsprockets. Chains and belts may comprise a wide variety of materialtypically used in the conveyor arts, for example, steel, rubber, etc.

[0019] Attached at intervals along the loops and extending laterallyacross the conveyor's width are a series of flights that travellongitudinally along the conveyor as the loops are rotated by therotation of the rotational elements. The rotational elements and hencethe loops and flights are located such that the flights are capable ofmoving debris longitudinally along the surface of the conveyor tray. Theflights are preferably somewhat flexible so that they may make somecontact and seal with the surface of the conveyor tray thus enabling theconveyance of water, mud and other fine debris. The flights may be madeof any suitable material known in the art, for example, aluminum, steel,rubber, plastic, or combinations thereof. Aluminum flights with rubberedges are particularly useful as they provide both strength andflexibility. The flights generally extend the width of the conveyortray, therefore, the flights may extend laterally beyond the loops ifthe distance between outside loops is less than the width of theconveyor tray.

[0020] A wide variety of drive means that may be used to drive theconveyor of the present invention are known in the art. Advantageously,motors may be used, preferably hydraulic drive motors. When a set ofrotational elements is independently supported on the conveyor tray orthe frame, it is possible to use more than one motor to drive therotational elements independently and to synchronize their speeds usingan electronic controller. However, for simplicity, a single motor isgenerally used to drive the first set of rotational elements, the firstset being connected by a laterally extending solid shaft. The drivemeans is preferably reversible to permit rotation of the rotationalmeans, and hence the loops, in either direction. This is particularlyuseful for clearing jams and cleaning the conveyor as the flights canthen travel longitudinally along the surface of the conveyor tray eithertoward the hopper or toward the roadway.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order that the invention may be more clearly understood, apreferred embodiment thereof will now be described in detail by way ofexample, with reference to the accompanying drawings, in which:

[0022]FIG. 1 is a side elevational view of a street sweeper of thepresent invention;

[0023]FIG. 2 is a top perspective view of the conveyor included in thestreet sweeper of FIG. 1; and

[0024]FIG. 3 is an exploded view of a spindle hub assembly included inthe conveyor of FIG. 2.

PREFERRED EMBODIMENT

[0025] With reference to FIG. 1, a street sweeper (1) includes a frame(5), wheels, a suspension, an internal combustion engine and otherstandard vehicle components. Supported on the frame (5) is a hopper (10)which receives debris from an inclined conveyor (20). The hopper (10)holds debris until it is emptied at a site and at least a portion of thehopper (10) has the general shape of a box with an upper open end. Theconveyor (20) comprises a conveyor tray (21) having a surface (22) whichreceives debris swept up off the roadway by a brush (15) located at therear of the street sweeper and rotating in a clockwise direction asviewed in FIG. 1. Drag shoes (17) located laterally on either side ofthe brush (15) minimize the amount of debris which is thrown laterallyfrom the street sweeper by the brush.

[0026] In order to move debris along the surface (22), a series oflaterally extending rubber edged aluminum flights (29) attached atintervals to a pair of laterally spaced apart parallel reinforced rubberbelts (28, one of the pair not shown) are in contact with the surface(22) and push debris up the surface (22) as the flights (29) travelupwardly due to clockwise motion of the pair of belts (28, one of thepair not shown). When one of the flights (29) travels in a clockwisedirection, a flight starting at the bottom of the conveyor tray (21)travels upwardly to push debris up the surface (22) to the top of theconveyor tray (21) where the debris is pushed off the end of the surface(22) to fall into the hopper (10). A flight at the top of the conveyortray (21) travels around the first pair of pulleys (24, one of the pairnot shown) and then travels down the conveyor tray (21) on the topsideof the belts (28, one of the pair not shown) until the flight reachesthe bottom of the conveyor tray (21) and once again contacts the surface(22) to push debris up to the hopper (10). Sequentially spacing theflights (29) on the belts (28, one of the pair not shown) helps ensurecontinuous movement of debris up the surface (22).

[0027] The pair of belts (28, one of the pair not shown) is supported onand engaged with a first pair of laterally spaced apart pulleys (24, oneof the pair not shown) proximate the longitudinal end of the conveyortray (21) located near the hopper (10). The pair of belts (28, one ofthe pair not shown) is also supported on and engaged with a second pairof laterally spaced apart pulleys (27, one of the pair not shown)proximate the longitudinal end of the conveyor tray (21) located nearthe brush (15). A third, smaller pair of laterally spaced apart pulleys(23, one of the pair not shown) also supports the belts (28, one of thepair not shown) at about the midpoint between the first and second pairof pulleys (24 and 27, one of each pair not shown). All the pairs ofpulleys (23, 24 and 27, one of each pair not shown) are rotationallysupported on the conveyor tray (21) to permit rotation of the belts (28,one of the pair not shown) as the first pair of pulleys (24, one of thepair not shown) is driven in a clockwise direction, as viewed looking atFIG. 1, by the action of a hydraulic motor (not shown).

[0028] An enlarged view of the conveyor can be seen in FIG. 2. In FIG.2, the belts (28 a, 28 b) are supported on and frictionally engaged withthe first pair of pulleys (24—one referred to as 24 a and the other as24 b (24 b not shown)) and are also supported on and frictionallyengaged with the second pair of pulleys (27—one referred to as 27 a andthe other as 27 b). A third pair of pulleys (23, one referred to as 23 aand the other as 23 b) rotationally supported on the conveyor tray (21)is connected by a shaft and is located about half way along the conveyortray (21) between the first pair of pulleys (24 a, 24 b) and the secondpair of pulleys (27 a, 27 b). The third pair of pulleys (23 a, 23 b)helps support the belts (28 a, 28 b) and is smaller in diameter than andlocated vertically higher on the conveyor tray (21) than both the firstpair of pulleys (24 a, 24 b) and the second pair of pulleys (27 a, 27b). The first pair of pulleys (24 a, 24 b) is connected by a solid shaft(25) and the shaft (25) is rotationally supported on the conveyor tray(21). A hydraulic motor (26) drives the shaft (25) which in turn drivesthe first pair of pulleys (24 a, 24 b), therefore, each pulley (24 a, 24b) is driven at the same speed. The rotation of the first pair ofpulleys (24 a, 24 b) drives the belts (28 a, 28 b), which in turn causesthe flights (29, only one of which is shown for greater clarity) totravel along the surface (22) of the conveyor tray (21). The hydraulicmotor (26) is reversible to permit either clockwise or counterclockwisemotion of the first pair of pulleys (24 a, 24 b) and of the belts (28 a,28 b) thus permitting the flights (29) to also push debris down thesurface (22) of the conveyor tray (21) to facilitate cleaning and forthe removal of jams.

[0029] Still referring to FIG. 2, the second pair of pulleys (27 a, 27b) is not connected by a shaft, thereby providing an unobstructedpassageway (40) in the lateral space between the second pair of pulleys(27 a, 27 b). The unobstructed passageway (40) permits larger debrisswept up by the brush (15) (not shown in FIG. 2) to pass between thesecond pair of pulleys (27 a, 27 b) to be deposited on the surface (22).The debris is then pushed up the conveyor tray (21) by the flights (29)off the end of the surface (22) to be delivered to the hopper (10) (notshown in FIG. 2). The second pair of pulleys (27 a, 27 b) is not drivenand rotates in response to movement of the belts (28 a, 28 b), therebyacting as idler pulleys. Scrapers (30 a, 30 b) are located just behindeach of the second pair of pulleys (27 a, 27 b) to help minimize buildupof dirt and other debris at the second pair of pulleys (27 a, 27 b).Each of pulleys (27 a, 27 b) is supported on the conveyor tray (21) by aspindle hub assembly (50 a, 50 b, respectively).

[0030]FIG. 3 depicts an exploded view of a spindle hub assembly (50 a)used at the lower end (second longitudinal end) of the conveyor of FIG.2. (It is understood that the following description of FIG. 3 alsoapplies to the corresponding spindle hub assembly (50 b) on the otherside of the conveyor tray (21) in FIG. 2). The spindle hub assembly (50a) includes a spindle hub and drum (51) on which the pulley is supportedand through which a spindle (52) is inserted. The spindle (52) is heldin the spindle hub and drum by a spindle nut (57), which is accompaniedby a spindle washer (56) and cotter pin (58) for additional security.The spindle (52) also passes through an inner bearing and an outerbearing located on either side of the spindle hub and drum (51). Theinner bearing comprises a bearing cone (54 a) and a bearing cup (55 a)and the outer bearing comprises a bearing cone (54 b) and a bearing cup(55 b). The bearings are generally packed in grease and allow for freerotation of the spindle hub and drum (51) around the spindle (52). Agrease seal (53) helps prevent dirt and other debris from getting intothe inner bearing. A dust cap (59), or optionally a grease cap, helpsprevent dirt and other debris from getting into the outer bearing. Thespindle hub and drum (51) is mounted on the conveyor tray by stud bolts(60) which are secured by stud nuts (61).

[0031] Other advantages which are obvious and which are inherent to thestructure will be evident to one skilled in the art.

[0032] It will be understood that certain features and sub-combinationsare of utility and may be employed without reference to other featuresand sub-combinations. This is contemplated by and is within the scope ofthe claims.

[0033] Since many possible embodiments may be made of the inventionwithout departing from the scope thereof, it is to be understood thatall matter herein set forth or shown in the accompanying drawings is tobe interpreted as illustrative and not in a limiting sense.

1. A conveyor for a mechanical street sweeper, the conveyor comprising:(a) a conveyor tray having a first longitudinal end, a secondlongitudinal end and a surface adapted to have debris conveyed thereon;(b) a first set of laterally spaced apart rotational elementsrotationally supported on the conveyor tray at the first end; (c) asecond set of laterally spaced apart rotational elements rotationallysupported on the conveyor tray at the second end defining a laterallyunobstructed passageway through which debris may pass between the secondset of spaced apart rotational elements; (d) a set of laterally spacedapart parallel loops supported on and engaged with the sets ofrotational elements and having laterally extending flights supported bythe loops at intervals along the loops, the loops and the sets ofrotational elements being located on the conveyor tray such that theflights travel along the conveyor tray to convey debris along thesurface; and, (e) a drive means connected to either the first or thesecond set of rotational elements for rotating the loops.
 2. Theconveyor according to claim 1, wherein the first set of rotationalelements is a pair of rotational elements, the second set of rotationalelements is a pair of rotational elements and the set of loops is a pairof loops.
 3. The conveyor according to claim 2, wherein the first pairof rotational elements is laterally connected by a solid shaft.
 4. Theconveyor according to claim 3, wherein the drive means is connected tothe first pair of rotational elements.
 5. The conveyor according toclaim 2, wherein the rotation of the loops is reversible.
 6. Theconveyor according to claim 2, wherein the rotational elements arepulleys and the loops are belts.
 7. The conveyor according to claim 2,wherein the rotational elements are sprockets and the loops are chains.8. The conveyor according to claim 2, wherein each of the second pair ofrotational elements is supported on the conveyor tray by a spindle hubassembly.
 9. The conveyor according to claim 8, wherein each spindle hubassembly comprises two bearings.
 10. The conveyor according to claim 9,wherein the bearings are packed in grease and each spindle hub assemblyincludes a grease seal and a dust cap.
 11. A conveyor for a mechanicalstreet sweeper, the conveyor comprising: (a) a conveyor tray having afirst longitudinal end, a second longitudinal end and a surface adaptedto have debris conveyed thereon; (b) a first pair of laterally spacedapart pulleys rotationally supported on the conveyor tray at the firstend and connected by a solid shaft; (c) a second pair of laterallyspaced apart pulleys rotationally supported on the conveyor tray at thesecond end by spindle hub assemblies and defining a laterallyunobstructed passageway through which debris may pass between the secondpair of spaced apart pulleys; (d) a pair of laterally spaced apartparallel belts supported on and engaged with the pairs of pulleys andhaving laterally extending flights supported by the belts at intervalsalong the belts, the belts and the pairs of pulleys being located on theconveyor tray such that the flights travel along the surface to conveydebris along the surface; and, (e) a drive means connected to the firstpair of pulleys for rotating the belts.
 12. A mechanical street sweepercomprising: (a) a frame; (b) a hopper supported by the frame for holdingdebris; (c) a brush supported by the frame for selective rotation incontact with a roadway; (d) an inclined conveyor tray supported by theframe and having a first longitudinal end proximate the hopper adaptedfor delivering debris to the hopper, a second longitudinal end proximatethe brush adapted for receiving debris from the brush and a surfaceadapted to have debris conveyed thereon; (e) a first set of laterallyspaced apart rotational elements rotationally supported on the frame orthe conveyor tray proximate the first end of the conveyor tray; (f) asecond set of laterally spaced apart rotational elements rotationallysupported on the frame or the conveyor tray proximate the second end ofthe conveyor tray and defining a laterally unobstructed passagewaybetween the second set of rotational elements through which debris maypass from the brush to the surface of the conveyor tray; (g) a set oflaterally spaced apart parallel loops supported on and engaged with thesets of rotational elements and having laterally extending flightssupported by the loops at intervals along the loops, the loops and thesets of rotational elements being located on the frame or the conveyortray such that the flights travel along the conveyor tray to conveydebris along the surface; and, (h) a drive means connected to either thefirst or the second sets of rotational elements for rotating the loops.13. The street sweeper according to claim 12, wherein the first set ofrotational elements is a pair of rotational elements, the second set ofrotational elements is a pair of rotational elements and the set ofloops is a pair of loops.
 14. The street sweeper according to claim 13,wherein the first and second pairs of rotational elements are supportedon the conveyor tray.
 15. The street sweeper according to claim 13,wherein the first pair of rotational elements is laterally connected bya solid shaft.
 16. The street sweeper according to claim 15, wherein thedrive means is connected to the first pair of rotational elements. 17.The street sweeper according to claim 13, wherein the rotation of theloops is reversible.
 18. The street sweeper according to claim 13,wherein the rotational elements are pulleys and the loops are belts. 19.The street sweeper according to claim 13, wherein the rotationalelements are sprockets and the loops are chains.
 20. The street sweeperaccording to claim 13, wherein each of the second pair of rotationalelements is supported on the conveyor tray by a spindle hub assembly.21. The street sweeper according to claim 20, wherein each spindle hubassembly comprises two bearings.
 22. The street sweeper according toclaim 21, wherein the bearings are packed in grease and the spindle hubassembly includes a grease seal and a dust cap.